Wandering the brightly lit halls of the 3D Systems’ plant in Rock Hill, South Carolina, I gaze upon objects strange and wondrous. A fully functioning guitar made of nylon. A phalanx of mandibles studded with atrocious-looking teeth. The skeleton of a whale. A five-color, full-scale prototype of a high-heeled shoe. Toy robots. And what appears to be the face of a human fetus. “That was made from an ultrasound image,” Cathy Lewis, the company’s chief marketing officer, tells me, shrugging.

This collection of objects shares one feature: All were “printed” by machines that, following instructions from digital files, join together layer upon layer of material—whether metals, ceramics or plastics—until the object’s distinctive shape is realized. The process is called 3-D printing (or additive manufacturing, in industrial parlance) and if you haven’t heard of it by now, you haven’t been paying enough attention to scores of breathless news stories and technology blogs—or to President Barack Obama, who declared in his most recent State of the Union address that 3-D printing “has the potential to revolutionize the way we make almost anything.”

While many people only now are hearing about the technology, engineers and designers have been using large and expensive 3-D printers for nearly three decades, making rapid prototypes of parts for aerospace, defense and automotive companies. Over the years, however, digital design software has matured, scanners have become ubiquitous and affordable desktop printers have come within reach of self-starting entrepreneurs, schools and home tinkerers. Technologists boisterously proclaim that 3-D printing will democratize design and free us from the he­gemony of mass manufacturing.

But just because anybody’s ideas can take shape doesn’t necessarily mean they should—a notion that struck me in 3D Systems’ lobby, where I saw shelf after shelf of what some people try very hard not to describe as cheap plastic crap: brightly colored miniature vases, phone cases, jewelry, dolls and, inevitably, skulls. (On just one 3-D file-sharing site, I found 101 designs for skull rings and pendants.) The creator of these lobby tchotchkes? The Cube, manufactured by 3D Systems.

“This is our consumer strategy,” Lewis explains to me, pointing toward a group of pink, turquoise and lime-green printers. The Cubes are the size of a Mr. Coffee machine, shiny and smooth, and have an on-off switch, a port for a thumb drive and a price tag of $1,299. Cubes create objects through a material extrusion process, in which a print head deposits and stacks thin layers of molten plastic onto a platform. The process begins when users load their digital design into the Cube, whose software helps them scale their model up or down and automatically adds support structures if they’re needed. (Supports are made of the same plastic as the machine prints, and they pop off.) Then the Cube “slices” the digital object into microns-thick horizontal layers, creating a blueprint that the print head will follow, moving on x and y axes.

The Cube can create objects in 16 different colors, but it can print only one color at a time (no cartridge switching mid-print). To make a toy robot or a skull ring in more than one color during a single printout, you’ll need a CubeX Duo, which costs more than twice as much but has two print cartridges that automatically turn colors off and on—a great leap forward in the eyes of desktop printing aficionados.

Perhaps sensing my ambivalence toward this device, Lewis leads me into a glass-walled manufacturing room to see the company’s big guns: a brace of refrigerator-size machines fronted with small windows and surrounded by monitors, keypads and CPUs. Electrical cables snake overhead, Shop-Vacs are ubiquitous and the floor is slippery with powdered nylon. Squinting and shielding my eyes from glare, I stare through the small window of a stereo­lithography machine, in which a vat filled with a photosensitive polymer is repeatedly blasted by a laser, triggering a chemical reaction that causes a thin layer of the viscous dark blue liquid to harden. Seconds pass, horizontal lightning flashes and a wiper distributes another layer of the resin.

Each layer is 50 microns thick, which is equal to one-twentieth of a millimeter. (The thinner the layers, the finer the resolution and the crisper the details.) The finished object rises while its build bed, or platform, sinks. What was this printer—which costs $170,000—producing? Lewis consults a monitor and surmises it’s jewelry, a ring of intricate design. I note that it’s a lot of machine to make a bauble, but Lewis assures me that technicians usually build more than one bauble at a time.

She shows me another windowed machine. This time the vat is filled not with dark blue liquid but white powdered nylon. A wiper smoothes the vat’s surface, upon which a laser lightly etches the outlines of four rings and a miniature boomerang by fusing together the powdered material (a process known as sintering). The wiper swipes again, erasing the shapes, the laser flashes, and another layer of rings and a boomerang is sintered. The monitor tells us this project is four inches high after 26 hours of sintering, with many hours to go. The “reveal” won’t come until the excess powder is excavated and the product exhumed. It might be a drone, it might be a cast for an engine block. Lewis can’t say (it’s definitely not a boomerang). But she knows this part will be as durable as whatever traditionally manufactured part it’s replacing.

My tour ends where it began, among the plastic robots and phone cases. In two hours, the history of additive manufacturing has passed before my eyes, starting with technical applications and ending in homes and offices—not unlike the trajectory of computers and laser printers. With the ability to replicate or create such objects on demand, says Dale Dougherty, publisher of Make magazine—part of the burgeoning DIY “Maker Movement” that privileges customization over commodities—the 3-D printer is “Wal-Mart in the palm of your hand.”

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